Hoisting apparatus for operating grab-buckets.



A. SMITH. HOISTING APPARATUS FOR OPERATING GRAB BUGKETS. APPLIUATION IILBD JUNE 12, 1913.

1969' Patented Apr. 7, 1914.

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Z o H L V J WITNESSES INVENTOR I ATTORNYJ srATEs PATENT erroneous entrant, or nosnELE, new JEnsEmnssIeNon T0 BERGEN rom'r more wonxs, or BAYONNE, NEW JERSEY, A ooEronATIoN or NEW JERSEY.

nominee cnram'rus Eon oraasrme GRAB-BUGKErs.

rwaem.

To all whom it may concern:

Be it known that I, A o sTUs SMITH, a citizen of the United States of America, and residing at Roselle, in the county of Union and. Stat of New Jers y, have invented a certain new and useful Improvement in Hoisting Apparatus for Operating Grab- Buckets, of which the following is'a specificatiou.

The present invention relates to an ims provement in hoisting ap aratus for operating rab buckets, especially grab buckets of the 0 am shell type, the present mechanism being an improvement in one type of apparatus shown in my copending application Serial Number 695,079 to whichreference is hereby made.

In the accompanying drawing Figures 1 and 2 are broken plan views of apparatus in which my invention is embodied in different specific manners.

Thehoisting apparatus to which the present improvement applies is of that general charactor in which two reversible motors are employed to turn two independent drums, on one of which (hereinafter called the holding drum) is wound the rope which raises and lowers the grab bucket, and on the other of which (hereinafter called the closing drum) is wound the rope which controls the opening and shutting of the grab bucket. As described in my application above mentioned, a friction drag device may be interposed be tween the drums so that they tend to revolve together, and'the holding drum may be connected to its motor through a ratchet and pawl mechanism which permits the holding drum to rotate under the drag of the closing drum while the holding motor is halted, but is positively. driven by the latter when started, since its pawl at once catches up with the slipping ratchet. The object of this feature is to keep the holding rope taut during the closing of the bucket but without lifting materially on the bucket since a lifting action would decrease the digging power of the bucket, which is dependent upon its weight for this function. A counterweight for the bucket is also employed but the use of the same introduces various complications and difliculties into the operation of the hoisting mechanism which it is the object of the resent invention to simplify.

Referring rst to the arrangement illus- Speoifiaatlen of Letters Patent. Application mes June 12, 1913.. Serial No. 773,266.

driving. gear comprising a gear 11 driven Patented Apr. 7, 191%. I

from motor H and carrying pawls 12 which engage the ratchetteeth 13 on the drum 7 to positively drive the latter in one direction while at the same time permitting it to slip ahead under the influence of the drag of the closing drum while the hoisting driving gear is still at rest. The hub 10 is extended past the bearing of the gear 11 and on its extended portion is cut a coarse pitch thread 1 1. This thread is engaged by the internally threaded hub 15 of the counterweight drum 16, the cooperating threads being so arranged that under the pull of the counterweight the drum 16 is screwed against the side of the gear 11 while it screws away from the latter when the holding drum overruns its ratchet on lifting the bucket or turning in that direction under the drag of the clolsing drum. The actual motion at this screw is of course very little since one drum screws up practically as fast as the other unscrews, the effect being that the counterweight rope unwinds as the holding drum rotates under the influence of the drag, but the counterweight does not balance the bucket and thus decrease its digging power, as it would, were it directly connected to rotate with the holding drum.

This arrangement of the drums and shaft with respect to each other can be varied considerably and it is optional which drum is keyed to the shaft, though one should be keyed to it so that for the major part of the hoist the drums and shaft will revolve in unison. Thus an equally efficient arrangement is'shown in Fig. 2. Here the holding drum 17 is keyed to the shaft 18 and its driving ratchet wheel 19 turns loosely on the shaft while the counterweight drum 20 is screwed on the shaft at 21. In this case the closing drum 22 with its driving gear 23 is mounted loosely on the shaft and is pressed position that both it and the bucket are at digging and closing action, thereby dimin drum by the spring 24;

a ainst the holdin D %e collar 25 pinned to the tor without the introduction of an equalizer gear whereby both motors can act upon the closing drum, as more fully explained in my above mentioned application Serial Number 695,079.

The particular advantage of the construction is, as above stated, that the counterweight drum automatically maintains the counterweight in proper relation to the hoisting mechanism and there is no possibility of the counterweight reaching such the top of their travel at the same time thereby necessitating a temporary halt in the work while readjustment of proper relations is effected, while at the same time the bucket is not counterweighted during its ishing its digging capacity, as it would be if the counterweight were directly connected to rotate with the holding drum.

I claim as my invention 1. In hoisting apparatus of the character described, a closing drum, a holding drum, a drag device between the same, motor means for rotating said drums, a one-Way drive connection therefrom to the holding drum, a counterweight drum, an operative connection therefrom to the motor means, and a connection between said holding drum and the counterweight drum, operative upon the overrunning of its drive connection by the holding drum under the influence of the drag of the closing drum, for freeing the counterweight from its operative connection tothe motor means whereby said drum -is free to rotate under the pull of its counterweight.

2. In hoisting apparatus of the character described, a holding drum, a motor, a oneway drive between said motor and holding drum, a counterweight drum, means for rotating the latter on the operation of the motor, and means controlled by the holding drum for permittin drum to rotate while t e motor is halted.

3. In hoistin apparatus of the character described, a ho ding drum, a motor, a oneway drive between said motor and holding drum, a counterweight drum, a friction clutch between said counterweight drum and motor andmeans controlled by the holding drum for freeing said clutch to permit the counterweight drum to'rotate while the motor is halted. 4. In hoisting apparatus of the character described, a holding drum, a motor therefor, a one-way driving connection between the same, whereby the drum may rotate while the drive is halted, a counterweight drum, a frictional drive connection to said motor maintained by the pull of the counter-. weight and means operative upon the rotation of the holding drum in advance of the motor for releasin the frictional driving engagement ofsaid counterweight drum whereby the latter is free to rotate under the pull of its counterweight, substantially as described.

5. In hoistin apparatus of the character described, a holding drum, a counterweight drum, a reversible motor, a one-way hoisting driving connection to the holding drum from said motor, and a clutch drive between the motor and the counterweight. drum to wind the counterweight upon the latter, in combination with means controlled by said holding drum and operative upon the rotation of the latter in advance of its drive for freeing said clutch drive to the counterweight drum to permit the latter to rotate the counterweight under the pull, of its counterweightalone,

substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

AUGUSTUS SMITH. 

